Gas discharge apparatus

ABSTRACT

The admission of a gas to a reaction chamber which has been previously evacuated is followed by its excitation by either a high-frequency electrostatic field or an electromagnetic field, formed by capacitor plates or a coil, respectively, which envelops the outer wall of the reaction chamber. A perforated metallic cylinder is disposed within the chamber concentrically with the long axis of the chamber and comprises the materialhandling zone of the chamber. The activated gas reacts with material placed within the perforated cylinder, during which reaction inactive gas and resultant gaseous byproducts are continuously withdrawn. The construction of the chamber and the internal perforated metallic cylinder are such as to provide very uniform distribution of gaseous excited species throughout the entire material-processing volume within the cylinder thereby promoting very uniform chemical conversions of practical interest.

United States Patent 1 Nakamura Sept. 9,1975

[54] NEEDLE DEFECT DETECTOR APPARATUS FOR CIRCULAR KNITTING MACHINES[75) Inventor: Isao Nakamura, Nishinomiya,

Japan [73] Assignee: Kazumasa Ashida and Shinko Electric andInstrumentation Co., Ltd., Osaka, Japan v [22] Filed: Apr. 24, 1974 [2]]Appl. No.: 463,536

[30] Foreign Application Priority Data Apr. 27. 1973 Japan .1 51441 [52]U.S. Cl 250/561, 66/165, 250/227 [51] Int. Cl. G01N 21/30 [58] Field ofSearch 250/559, 561, 562, 563,

[5 6] References Cited UNITED STATES PATENTS 3,631,690 1/1972 Findlay etal 66/165 3,599,586 8/1071 Newman 242/36 3,772,524 11/1973 Erbstein250/561 3,496,739 2/1970 Motin et al 250/571 3,688,526 9/1972 Worner66/165 11/1969 Kottman ..250/563 8/1972 Flaczynski ..250/560 PrimaryExaminer-Eli Lieberman Assistant Examiner- D. C. Nelms Attorney, Agentor Firm-James E. Nilles 1 ABSTRACT This invention relates to anapparatus for detecting defects of needles for a circular knittingmachine.

Said apparatus comprises at least an optical fiber having an end of asmall sectional area and disposed to detect light reflections from oneof hooks or latch portions of dial and cylinder needles mounted on thecircular knitting machine, a light receiver unit operatively coupled tothe other end of said optical fiber and including a photo-electricconverter element, and an electric circuit for transforming a variationin signal representative of said light reflections produced by saidlight receiver unit into a corresponding variation of an electricalquantity.

In this invention possible breaking or bending of the hook or defects ofthe latch or like undesirable conditions of the knitting needles aredetected to thereby prevent knitting defects from being produced in theknitted web.

3 Claims, 7 Drawing Figures PATENTED SEP 9 I975 SHEET FIG. I

PATENTED SEP 9 I975 SHEET HRDQ hr D FIG. 3A

PATENTED 9l975 3,904,529

SHEET 3 FIG. 5

9 l I 27 28 30 3| 32 f $229 j SWITCHING CIRCUIT AMPLIFlER AND 5% j ENDOF FIBER CIRCUIT 2 BUNDLE AND GATE Z CONV/TER 29 RECEIVER CIR T 30 9 I I27 28 DISPLAY UNIT NEEDLE DEFECT DETECTOR APPARATUS FOR CIRCULARKNITTING MACHINES BACKGROUND OF THE INVENTION otherwise occurringdefects from being produced in.

the knitted web.

Lately, a photo-electric detection system is rather increasingly usedfor automatically detecting defects in a web knitted by a circularknitting machine. However, it is difficult to perform such detection forthe knitted web itself in case of a pattern knitting or av coloredpattern knittingwhich is widely employed in the circular knitting field.Considering the fact that most of the knitting defects or defectivestitches are attributable to malfunctions or defects of the knittingneedles, it is apparently more advantageous to instantly stop theoperation of the machine by detecting the defects or malfunctions of theknitting needles themselves to thereby previously exclude thepossibility of the defects being produced in the knitted stitches thanto detect the defects in the knitted web to thereby stop the machineoperation. In order to monitor heads or points of the knitting needles,the detection has to be performed when the knitting needles areprojected. In case of the circular knitting machine, the detection mustbe made at a position adjacent to the yarn feeder or at the positionwhere the needles are at least partially projected. Accordingly, it isnecessary to use a detector of a very small size. Particularly, in caseof a circular knitting machine which has needles arranged at a highdensity and is rotated at a relatively high speed, the thickness of theneedle head is only of 0.3 to 0.4 mm and therefore a detector head of aspecial design was required for the valid detection. I

The present invention has overcome the above difficulties by using anoptical fiber or fiber bundle having a diameter of ca. 0.5 mm as thedetector head.

Accordingly, an object of the present invention is to provide a needledefect detection apparatus comprising an optical fiber bundle fordetecting the defects of the needles as variations in light reflectedfrom the needle head and impinging onto the exposed end of the opticalfiber.

In a lately developed circular knitting machine operated at a higherrotating speed as compared with prior machines, oil mist is used forlubrication. Because no optical lens system is employed in conjunctionwith the optical fiber bundle in the apparatus of the present invention,the use of oil mist will provide substantially noobstacle for the lightreceiving function, since the'adhesion of oil mist to the optical lensdoes not come into question. Additionally, the apparatus according tothe invention may be operated under sufficiently stabilized conditionwithout being subjected to disturbance by dispersed yarn dusts.

The apparatus according to the present invention allows the use of allelectronic components for an electric signal processing circuit as wellas alarming circuit for a control section except for a mechanism whichserves to stop the operation of the knitting machine by means of relaycontacts. Furthermore, according to the present invention, theelectronic signal processing circuit includes a means for converting theinterval period between succeeding adjacent pulses produced by twoadjacent knitting needles into a voltage wave form having acorresponding amplitude and a circuit for producing a signal to stop theoperation of the knitting machine when there occurs a voltage of anabnormal amplitude twice as great as said corresponding amplitude. Dueto such circuit arrangement, the detector apparatus of the presentinvention is prevented from being operated during the initiation phaseof the machine operation until the machine attains a predeterminedconstant speed. The time span of the initiation phase may be arbitrarilyselected. Additionally, the detector apparatus does not function duringthe deceleration phase of the machine operation as brought about by thesignal representative of a defect of the needle.

A plurality of detector channels are provided, each having a displaydevice such as a lamp so that the defective needle detected by adetector channel may be easily identified by the associated displaylamp.

For a knitting machine of a single needle type, the

.provision of a single detector head will be sufficient.

For a knitting machine of a double needle type in which no needleselecting operation is required, two detector heads, i.e. one for dialneedles and the other for cylinder needles will be sufficient. In caseof the machine where the needle selection is to be made, four detectorheads are required. For the circular knitting machine the cylinderneedles of which are operated in the so-called tuck position, threedetector heads, namely one for cylinder needles and two for dial needlesare required.

The above and other objects as well as novel features and advantages ofthe present invention will become more apparent from the followingdescription of a preferred embodiment of the invention. The descriptionmakes reference to drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially sectionedfragmental side view of a knitting portion of a circular knittingmachine of a double needle type illustrating a detector apparatusaccording to the present invention mounted for monitoring hook portionsof cylinder needles;

FIG. 2 schematically illustrates a relationship between needles andactuating cams;

FIGS. 3A and 3B are front and side views, respectively, of a detectorhead for the hooks of cylinder needles mounted on a dial needle exchangecover;

FIGS. 4A and 4B are front and side views, respectively, of a detectorhead mounted on an inherent yarn feeder of the machine for monitoringthe hooks of dial needles; and

Fig. 5 is a block diagram of an electric circuit having two detectorheads or channels.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT Referring to FIG. 1,reference numeral 1 indicates a dial provided with a dial cover 2.Numeral 3 denotes dial cams for controlling the operation of dialneedles 4. Reference numeral 5 denotes a needle cylinder provided with acylinder cover 6. Cylinder cams 7 are also arranged for operatingcylinder needles 8. Further, reference letter A represents hook portionsof the needles 4 and 8, respectively, while character B denotes latchportions of the respective needles 4 and 8. Letter C denotes bretts eachof which constitutes a part of the needles 4 and 8 and is adapted tocooperate with the associated cam to move the needle reciprocately.Usually, the dial'l and'the cylinder 5 are rotated with the needles 4and 8 placed in the needle grooves, while the dial cover2 and thecylinder cover 6 remain stationary and serve to support the associatedcams 3 and 7. Reference numeral 9 indicates an end portion of an opticalfiber bundle which end portion is held in a position apart from the hookportion A for a distance less than a few millimeters and serves as asensor or detector head. The optical fiber bundle 9' is accommodatedwithin a holding metal tube 10 and operatively coupled to a light signalreceiver unit '11 comprising a photoelectric converter element and anamplifier in a form of an integrated circuit. The receiver unit 11in'turn is electrically connected to a control section for processingelectric signals, as will be hereinafter described. Numeral 12 indicatesa light emission or illuminating element energized by dc. current fromwhich ripple components have been completely removed. The light emissionelement12 as well as the light receiver unit 11 are supported by a frame13 which is mounted on the cylinder cover 2 at 14 removably so that theframe 13 together with the light emission element 12 and the receiverunit 11 may be removed or moved away from the needle heads so as tofacilitate manual works such as exchange of yarns or the like. An arrowD indicates the direction into which knitted web is fed or forwarded.

Referring to FIG. 2, which illustrates a relationship between theneedles 4 and 8 and earns for pushing and withdrawing them, numeral 15denotes cams for pushing the needles 4 and 8 to respective middle orintermediate positions generally called tuck posi tion, while numeral 16indicates cams for returning these needles 4 and 8 from the tuckpositions to the starting positions. Further, cams 17 serve to push theneedles to the outermost positions, which needles are then movedbackwards by respective cams 18. Dots 19 schematically indicate thepositions of the bretts. The outermost positions of the needles forlatching yarns into the hooks are indicated by numeral 20 and the tuckpositions are denoted by reference numeral 21. Arrow E indicates thedirection in which the dial 1 or cylinder 5 carrying its needles isrotated.

FIGS. 3A and 3B show a detector head for the hooks of cylinder needles.

In FIGS. 3A and 38, reference numeral 22 indicates an inherentlyprovided portion of the machine for exchanging the dial needles. Whenthe head portions of needles for a pattern knitting machine are to bemonitored, the detector head may be easily mounted on this dial needleexchange portion 22 in a simple manner. To this end, a plate 23 isprovided for mechanically connecting the detector head to the dialneedle exchanging cover 22. The light receiver unit 11 and the lightemission element 12 are supported and secured to the plate 23 by meansof a member 24.

The light receiver unit 11 is electrically connected to a controlsection by way of an electric cable 25.

FIGS. 4A and 4B show a detector head for the hooks of dial needles.

In FIGS. 4A and 4B, yarn fed to the knitting machine is indicated byreference numeral 26.

Referring to FIG. 5, blocks 27 indicate amplifier and shaper circuits inwhich electric signalsproduced by the units 11 in response to theoptical inputs from the detector. head or optical fiber bundles areconverted into rectangular wave pulses of narrow pulse width. Connectedto the outputs of the circuits 27 are converter circuits 28 which arearranged so as to transform normally a distance or interval between thesucceeding adjacent pulses into an analog voltage signal of acorresponding magnitude and produce a voltage of the amplitude twice ashigh as said magnitude when a failure or defect is detected in a singleneedle. Blocks 29 represent limiter. circuits which are switched fromonestate to another state when the associated output voltages from thecircuits 28 vary from the normal amplitude to the high level as abovestated. The circuits. 29 have respective display units 30 suchas alarmlamps which are activated when the failure signals are produced in theassociated channels. The. outputs from the limit or switching circuits29 are coupled. to a coincidence comparator suchas an AND gate 31 whichin turn is connected to another switchingcircuit 32 for producing asignal to stop the operation of the knitting machine or an alarm signal.

The circuit 29 is constructed in a form of a priority the pulse intervalbecomes disordered, any defect representative outputs of the circuits 28will not exert any influences on this stopping phase of the machineoperation. I

Upon initiation of the circular knitting machine, the switching circuit32 is automatically released from the locked state. However, a timerrelay maybe employed in order to inhibit the defect detecting functionof the photo-electronic systems until the machine has attained apredetermined constant speed.

Although the invention has been illustrated and described with referenceto a preferred embodiment by way of an example, it will be appreciatedby those skilled in the art that modifications and changes may be madein the form of the invention without departing from the spirit and scopeof the invention.

What is claimed is:

1. Apparatus for detecting defects of needles for unit into acorresponding variation of an electrical signal, whereby a possibledefect of said component is detected to thereby prevent knitting defectsfrom for stopping the operation of the circular knitting machine whenthe voltage from said circuitry attains a level greater than saidpredetermined amplitude.

3. Apparatus as set forth in claim 2, further comprisr ing a circuit forinhibiting stoppage of the said machine after starting of the circularknitting machine until the machine has attained a predetermined constantspeed.

UNITED STATES PATENT OFFICE CERTIFICATE OF CQRRECTION Patent 3,904 ,529Dated September 9 1975 Inventor(s) I530 Nakamura It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

On the cover sheet the illustrative figure should appear as shown below:

Signed and Scaled this eleventh of May 1976 [SEAL] A ties I:

RUTH C. M A SON C. MARSHALL DANN AIH'SIHIX ()fjujvr ('mnmissimwruflarenls and Trademarks

1. APPARUTUS FOR DETECTING DEFECTS OF NEEDLES FOR A CIRCULAR KNITTINGMACHINE COMPRISING COMPONENTS INCLUDING HOOKS AND LATCH PORTIONS OF DIALAND CYLINDERS NEEDLES, COMPRISING A LIGHT SOURCE, AN OPTICAL FIBERHAVING AN END DISPOSED TO DETECT LIGHT REFLECTIONS OF SAID LIGHT SOURCEFROM AT LEAST ONE OF SAID COMPONENTS MOUNTED ON THE CIRCULAR KNITTINGMACHINE, A LIGHT RECEIVER UNIT OPERATIVELY COUPLED TO THE OTHER END OFSAID OPTICAL FIBER AND INCLUDING A PHOTO-ELECTRIC CONVERTER ELEMENT FORPRODUCING AN OUTPUT SIGNAL, AND AN ELECTRICAL CIRCUIT FOR RECEIVING ANDTRANSFORMING A VARIATION IN SAID OUTPUT SIGNAL REPRESENTATIVE OF SAIDLIGHT REFLECTIONS PRODUCED BY SAID LIGHT RECEIVER UNIT INTO ACORRESPONDING VARIATION OF AN ELECTRICAL SIGNAL, WHEREBY A POSSIBLEDEFECT OF SAID COMPONENT IS DETECTED TO THEREBY PREVENT KNITTING DEFECTSFROM BEING PRODUCED IN THE KNITTED WEB.
 2. The apparatus of claim 1wherein said reaction chamber has a generally cylindrical shape andwherein said means for forming a gaseous plasma within said chamberincludes a coil disposed about the outer wall of said chamber.
 3. Theapparatus of claim 1 wherein said reaction chamber has a generallycylindrical shape and wherein said means for forming a gaseous plasmawithin said chamber includes a pair of capacitor plates disposed on theouter wall of said chamber.
 5. The apparatus of claim 1 wherein saidmetallic structure is coated with a material unaffected by excitedgaseous species formed within said chamber.
 6. The apparatus of claim 1wherein said metallic structure comprises a cylindrical screen. 7.Apparatus for reacting a gas with a material in the influence of an rfelectromagnetic field comprising: an evacuable reaction chamber having agenerally cylindrical shape, closure means at one end of said chamberfor introducing material to be modified by reaction into said chamberand for removing modified material from said chamber, means forintroducing a gas within said chamber, means for withdrawing the gasfrom said chamber, means including a coil disposed about the outer wallof said chamber for forming an rf electromagnetic field within saidchamber, and a perforated metallic cylinder coaxially disposed withinsaid chamber, said perforated metallic cylinder providing a materialprocessing zone therewithin substantially unaffected by nonuniformlydistributed and field-perturbed gaseous ionized species formed withinsaid chamber external of said cylinder.